The newest Soft Kriture - Lumpy Space Princess - is available to pre order until July 11th 2013. Limited to only 7 pieces, the 4.3" tall handmade plush actually squeaks. You can pick one up for $40.00. (And the obligatory legalese from Soft Kriture land below)
The original character belongs to Adventure time but the design and techniques are the same used to craft a typical Soft Kriture, It's a fan art piece, I do not own any of the characters in the adventure time franchise.